SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '502ac9b7af7ea13d7b174988236fbca0b3b880007be9da6aad5a03b0a9d6639a' 
  AND token = 'o7Uv8f0+B5sochJ8453KMEgrEikktnpEh1dxu8XFRZo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}